Dyes used in color photographic materials are susceptible to degradation caused by a variety of environmental factors. For example, dyes can be faded by exposure to light of various wavelengths and intensities. In some instances, the fading of dyes by light is exacerbated by the presence of oxygen. Moisture can also have a deleterious effect on the stability of photographic dyes.
A variety of methods have been proposed to restrict the access of such agents as oxygen and water to photographic images. For example, extruded polyolefin layers to increase the moisture resistance of papers used for photographic prints have been disclosed in U.S. Pat. Nos. 3,411,908; 3,630,740; 4,042,398; 4,517,285; and 4,665,014.
U.S. Pat. No. 4,645,736 discloses a waterproof paper support containing a layer of radiation hardened varnish, and with a polymeric barrier layer such as a polyolefin positioned between the varnish layer and the paper. A waterproof support in which a layer of hardenable acrylic resin is applied between the paper and a polyolefin layer is disclosed in U.S. Pat. No. 4,729,945.
U.S. Pat. No. 4,283,486 discloses an oxygen impermeable or oxygen barrier layer comprising a vinyl alcohol polymer or copolymer positioned between a paper support and a color image-forming layer. A cover sheet or protective layer to restrict oxygen located above the light-sensitive layer is disclosed in U.S. Pat. No. 4,945,025.
U.S. Pat. No. 4,614,681 discloses a polyester film support in which an oxygen barrier layer comprising a copolymer of ethylene and vinyl alcohol is coated on the back side or on both sides of the support.
A paper support of low air permeability having a coating of a hydrophobic polymer on one or both sides of the paper is disclosed in U.S. Pat. No. 4,861,696, which further suggests that a waterproofing agent can be added to the hydrophobic polymer layer.
EP Application No. 391373 discloses a photographic paper support impregnated through the surface with a low level of a synthetic polymer such as a polyacrylamide or a polyvinyl alcohol as a paper strengthening agent.
It is especially desirable to improve the stability of full color photographic prints, composed of yellow, magenta, and cyan dyes, which are produced on paper supports and are frequently displayed. The previously mentioned U.S. Pat. No. 4,283,486 reports improvement in the stability of dyes exposed to 200,000 lux high intensity xenon illumination. Although protecting the dyes of a color photographic print against the effects of high-intensity light exposure is important, it is even more important from a practical standpoint to maximize their stability to conditions of prolonged low-intensity exposure. Furthermore, it is highly desirable that any dye fade that does occur be neutral, that is, the density of each dye decreases by approximately the same amount.